The Sun expected to ride out a looming galactic merger

The Large Magellanic Cloud, a satellite galaxy of the Milky Way. Image: Zdeněk Bardon/ESO

Studies indicate the Large Magellanic Cloud, a satellite galaxy some 160,000 light years away, will crash into the Milky Way in about 1.5 billion years, likely “waking up” the currently passive, supermassive black hole lurking at our galaxy’s core.

As a result of the merger, the black hole “will increase in mass by up to a factor of eight,” writes Marius Cautun, a postdoctoral fellow at Durham University’s Institute for Computational Cosmology and lead author of a paper in the Monthly Notices of the Royal Astronomical Society. “The galactic stellar halo will undergo an equally impressive transformation, becoming five times more massive.”

Most of the additional stars will come from the Large Magellanic Cloud, but a “sizeable number” will be ejected into the halo from the galactic disc.

“If energetic enough, γ-rays impinging on the Earth can cause mass extinctions by destroying the planet’s ozone layer. However, the galactic AGN will not be powerful enough to deplete the Earth’s ozone layer and is very unlikely to pose a serious danger to terrestrial life.”

But the merger will gravitationally eject central disc stars into the halo.

“Is the Sun a potential victim? Thankfully, this seems unlikely, as only a few per cent of the stars at the position of the Sun in our MW–LMC analogues are kicked out into the halo.”

Related Articles

This NASA/ESA Hubble Space Telescope image shows a stellar nursery known as N159 — a maelstrom of glowing gas and dark dust within one of the Milky Way’s satellite galaxies, the Large Magellanic Cloud (LMC). N159 is located over 160,000 light-years away. It resides just south of the Tarantula Nebula, another massive star-forming complex within the LMC.

Australian astronomers are in the process of collecting the spectra of a million stars across the Milky Way in a project to study galactic evolution. In the process, they hope to track down at least some of the sun’s lost siblings.

Astronomers have discovered a ‘treasure trove’ of rare dwarf satellite galaxies orbiting our own Milky Way. The closest is about 95,000 light-years away, while the most distant is more than a million light-years away.

Astronomy Now NewsAlert

Get the latest astronomical news and stargazing tips delivered to your inbox.